Microstructure and properties of ultra-fine grain Cu–Cr alloy prepared by equal-channel angular pressing

Ultra-fine grain (UFG) Cu–Cr alloy is prepared by equal-channel angular pressing (ECAP). The microstructure, tensile and fatigue properties of the UFG Cu–Cr alloy were investigated. The bulk materials with average grain size of ∼230 nm were obtained through ECAP for 12 times. The cellular subgrains with low-angle grain boundaries were first formed at relatively low strains, and high-angle grain boundaries dominate the microstructure with the increasing of strains. Materials exhibit homogeneous equiaxed subgrains after ECAP processing. The Cu–Cr alloy processed by ECAP has high strength besides high conductivity and sufficient ductility. Fatigue experiments were carried out in terms of stress-controlled for the 4 and 6 passes ECAPed samples. The increase of fatigue limit and prolong of fatigue life are remarkable as compared with those of coarse grain Cu–0.75Cr alloy and ECAPed pure Cu reported in available literatures.